Vibrator device



F. MARTI VIBRATOR DEVICE June 3, 1969 Filed Oct. '7, 1966 E fo 1b E@ INVENTOR:

22a Fig/7 2 AWA 7*/ ATTOR United States Patent O1 flce 3,448,304 VIBRATOR DEVICE Fritz Marti, La Chaux-de-Fonds, Switzerland, assignor to Portescap, Le Porte-Echappement Universel S.A., La Chaux-de-Fonds, Switzerland Filed Oct. 7, 1966, Ser. No. 585,095 Claims priority, application Switzerland, Oct. 7, 1965, 13,858/ 65 Int. Cl. H02k 33/06 U.S. Cl. 310--15 8 Claims ABSTRACT F THE DISCLOSURE The present invention relates to devices for producing continuous vibratory motion at a constant frequency. More particularly, this invention relates to constant-frequency vibrators for timepieces in which the vibrations are sustained electrically.

The use of a vibrator of the type disclosed herein in an oscillator arrangement for watches is described in greater detail in my copending U.S. patent application Ser. No. 585,129, filed on Oct. 7, 1966, and the disclosure of that copending application is incorporated herein by reference. Briefly, in such an oscillator arrangement the vibrator is maintained in vibration at a constant frequency by an electrical drive arrangement. When it is used in a watch, the vibrator either is directly coupled to a ratchet mechanism to drive the watch hands, or generates a constant-frequency electrical signal which is used to energize a seperate synchronous drive arrangement which turns the watch hands. In either arrangement, the uniformity of the vibration frequency is important in maintaining the accuracy of the watch at a high level.

One type of vibrator is the torsion vibrator in which an elongated metallic blade is flexed tortionally to provide a resilient return force for the member which is vibrating. The present invention solves problems particularly troublesome in this type of vibrator.

A major problem with torsion vibrators is that of preventing undesired fiexing or bending of the torsion blade. Such llexing or bending causes parasitic vibrations of the blade which tend to impair the operation of the oscillation device.

A preferred embodiment of the torsion vibrator of the present invention includes at least one flat resilient blade rigidly fastened at its ends to a rigid support member. The blade has at least one central portion twisted in such a manner as to be located in the same plane as the axis of oscillation of the two ends of the blade, and forms an angle with the plane of the blade ends. The plane of the central portion of the blade preferably is at least vapproximately perpendicular to that of the two ends,

which results in a high resistance to flexing in two perpendicular planes and, therefore, in practically any direction.

The accompanying drawing shows various embodiments `of the vibrator of the present invention.

3,448,304 Patented June 3, 1969 FIGURE 3 and 4 are plan and side views of another embodiment of the invention; and

FIGURES 5 Iand `6 are plan and side views of a third embodiment of the invention.

The vibrator shown in FIGURES 1 and 2 includes a rigid support member 1 shaped like a stirrup. Between the ends of the two arms of support member -1 there is fastened a flat blade 2. The two end portions 2a of blade 2 are secured to the arms of support member 1 preferably by riveting or welding, and are arranged in a plane parallel to that of the support member 1. The central portion 2b of blade 2 is twisted 90 and is, therefore, arranged in a plane which is perpendicular to the plane of the two end sections 2a and in which is located the axis of oscillation of the sections 2a. The length of the central portion 2b is approximately equal to half of the total active length of the blade; that is, half of the length of the blade between the points at which it is secured to the support member 1.

To the center of the central portion 2b of the blade there is secured an oscillating arm 3 having at one end an electromagnetic oscillating sustaining system 4 and, at the other end, a counterweight `5. The arm oscillates clockwise and counterclockwise about the longitudinal axis of the blade 2, as is indicated by the arrow 5w. The oscillation sustaining device 4 periodically pulls one end 0f the arm 3 downwardly (as the device is shown in FIGURE 1) against the resistance of the counterweight 5 and the blade 2, and then the restorative forces of the blade and the counterweight cause that end of the arm to rise above and then fall downwardly from an equilibrium position, and then the cycle is repeated.

The oscillation sustaining system 4 comprises a U- shaped ferromagnetic support I6 provided with two permanent magnets 7 bonded to the insides of its arm. This structure cooperates with a two-winding coil 8 including a signal winding and a driving winding, wound on a fixed frame (not shown) and connected to a transistorized circuit Tr. This arrangement operates in a known manner to apply pulsating forces to the end of the arm 3 to sustain the' oscillation of the arm as described above.

In the vibrator shown in FIGURES 3 and 4, two parallel flat resilient blades 12 are provided instead of one. Both blades 12 are formed from a single sheet of metal 11 which forms the support structure for the blades. Each blade |12 has two end portions 12a located in the same plane as the support 11, and a central portion 12b which is twisted and, therefore, is located in a plane which is perpendicular to the plane of the support 11 and contains the axis of oscillation of the blade. The two blades 12 are staggered in a longitudinal direction with respect to one another.

The vibrator shown in FIGURES 5 and 6 also is rformed from a single ilat sheet 21, and also has two parallel blades 22. Each of these two blades also has two end portions 22a located in the same plane as their common support member 21, and a central portion 22b twisted 90 and located, therefore, in a plane which is perpendicular to the plane of the support member 21 and contains the aixs of oscillation of the blade.

Each of the support members 11 and 21 has holes near the blade ends 22a for securing the device to an appropriate mounting surface.

The parallel-blade vibrator blade arrangements shown in FIGURES 3 through 6 are particularly useful in the oscillator devices described in my above-identified c0- pending patent application in which dual contra-oscillating arms are provided. That is, asis described in greater detail in my above-identified copending U.S. patent application, secured to each torsion blade near its center is an arm which is provided at one of its ends with a magnetoelectric vibration-sustaining device, and at the other end with a counterweight. The twoarms oscillate in opposite directions, and the entire assembly is shaped and constructed in a manner such that at all times and regardless of the position of the mechanism, the torques on the torsion blades are of the same magnitude but are oppositely directed. Also, the torques are applied in the same plane or in parallel planes. As a result, substantially no torque is transmitted by the support member to the timepiece mechanism or its case.

The above description is not intended lto be limiting; on the contrary, it is intended merely to be illustrative of the different embodiments of the invention which can be devised. Another embodiment of the invention includes, for example, two torsion blades, each with a twisted central portion, one twisted 45 in a clockwise direction, the other twisted 45 in a counterclockwise direction. Still another embodiment has a single blade with a central portion divided into two sections, one of which is twisted counterclockwise and the other is twisted clockwise. Other embodiments can be devised without avoiding use of the present invention as it is defined by the following claims.

`I claim:

1. In a vibrator device of the type described, a relatively rigid support member, and at least one flat resilient blade secured at its two ends to said support member, at least one central portion of said blade being twisted so as to be located in a plane Iforming an angle with the plane of the remainder of said blade, an oscillation `arm secured to said blade, and means for sustaining the oscillation of said arm about the axis of said blade.

2. A device according to claim 1, in which said central portion of said blade is located in a plane which is perpendicular to the plane of its two end portions and contains the axis of oscillation of said blade.

3; A device according to clairnvl, in which said central portion of said blade has alength approximately equal to at least half of the total active length o=f said blade.

4. A device according to claim 1, characterized by the fact that the blade is integral with its support.

5. A device according to claim 1, including two of said blades arranged in substantially parallel relationship to one another.

'6. A device according to claim 5 in which said blades are integral with said support member.

7. A device according to claim 5 in which said blades are staggered longitudinally with-respect to one another.

8. A device according to claim 1 including a counterweight at one end of said arm, said arm being secured to said central portion of said arm, and said oscillation sustaining means being located at the other end of said arm.

References Cited I. D. MILLER, Primary Examiner.

Us. C1. XR.

sis-23, 116., 31o-26; 31a- 12s, 21s 

